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Full text of "The manufacture and properties of iron and steel"

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152                         METALLUEGY OP IRON AND STEEL.
Jiiptner loses 25.9 per cent, in producer ash against 2.1 per cent, at Steelton. Of the 74.1 per cent, actually utilized, von Jiiptner gets 50,7 per cent, potential in the gas, or only 68 per cent, of the potential of the coal consumed. But of the 97.8 per cent, utilized at. Steelton 78.4 per cent, is potential in the gas, or 80 per cent, of the potential of the coal. The Steelton practice is, therefore, 26.7 per cent, better in burning the coal and 10 per cent, better in utilizing the combustion for the making of gas. The former advantage is due to better construction and operation; the latter to the steam jet, which transfers 10 per cent, of the energy in the coal from the producer to the furnace.
The following conclusions may be drawn from the tables :
(1)  A producer demands one-quarter to one-fifth of all the heat value of the coal, delivering the remainder as potential in the gas.
(2)  If the loss of coal in the ash is very high, the gas may contain less than half the value of the coal.
(3)   The heat produced by the combustion of the silicon, carbon and iron of the bath is one-seventh as much as is supplied by the combustion of the gas.
(&) The heat from, the combustion of the metalloids and of the iron is one-half the quantity necessary to heat and melt the charge.
(5)   The distribution of heat in the open-hearth furnace must be calculated in percentages of the sum of the heat supplied by the gas plus the heat supplied by internal combustion.
(6)  About one-half of all the heat supplied to an open-hearth furnace is lost by radiation and conduction.
(7)  About one-quarter of the heat is lost in the waste gases going to the chimney.
(8)  About one-quarter of the heat is utilized in. heating and melting the stock.
These conclusions are founded on experiments where the coal consumption throughout the month was 500 pounds per gross ton of steel ingots. Where the coal consumption is higher, the percentage of heat utilized will be less, and the amount lost by radiation and in waste gases will be greater. The total loss in waste gases at Steelton was 23.4 per cent, of the total value of the coal, and the gases escaped to the stack at an average temperature of 680, this average being based on an estimate of the proportional amount escaping from the two chambers, the temperature of each